by Dennis Collin
When producing drawings for any discipline there is frequently the need to assign a linetype to elements that represent something significant in a drawing. From pipework in a building, to cables or fences on a site plan, or reference lines in sections and elevations.
Fig 1. A linetype definition file is just a text file describing line patterns and can be edited with notepad if desired.
Whilst AutoCAD does have some sample linetypes which should be adequate for typical scenarios, there is often a need to create linetypes specific to certain disciplines i.e. Surveying, infrastructure and so on. Whilst the linetype definition file can be edited within notepad, it is somewhat tedious understanding the syntax where positive numbers indicate lengths of line and negative numbers as spaces, zeroes as dots and complex codes for text or shape elements. For example, for linetypes using shapes U references the shapes rotation angle rather than using a logical code such as ‘R’.
Fig 2. Editing complex linetypes can catch users unaware!
S is easier to decipher, being size and X and Y are just offset controls. However, for users who rather create their complex linetypes graphically can use AutoCAD’s linetype creation Express Tool! These bespoke definitions can then be saved to AutoCAD’s (‘LIN’) Linetype definition file.
Fig 3. Drawing custom linetypes on screen using ‘paper units’.
To get start simply draw the desired linetype pattern as desired on screen. Draw elements at ‘paper units’ i.e. Line length at about 15 millimetres, and text or symbols at about 2.5 millimetres. Leave suitable gaps as required.
Fig 4. Accessing the Linetype creation command (Under Express Tools)
Access the Linetype creation command, create a new or append to an existing definition file using the steps below.
Select a ".LIN" file: <X:\CADRESOURCE\Settings\Metric.lin>: Enter a linetype file name and folder path
- Enter linetype name: Specify a linetype name
- Linetype description: Specify a linetype description
- Starting point for line definition: Specify a starting point
- Ending point for line definition: Specify an ending point
- Select objects: Select a line, polyline, point, shape, or text object
If selecting an existing LIN file, a warning dialog states that the file will be replaced; however, the file is appended to. If choosing to create a linetype with the same name as an existing definition, an overwrite warning appears. By choosing yes, the existing linetype is overwritten, but the remainder of the file remains intact. If in doubt it may be advisable to ensure bespoke linetype files are backed up first.
Fig 5. Post and Rail fence linetype set to a fence layer.
Once defined, the linetypes can be loaded into a drawing or template and then set to layers or entities as desired. If using complex linetypes as per the example above, for best results, set the LTGEN setting to on within the Pedit command or the properties palette. Creating linestyles is a more advanced topic but can be covered on our bespoke AutoCAD courses, templates, and our Intermediate AutoCAD courses. For more information on this call us on 0330 551 9420 or visit Arkance.world